SALT LAKE CITY — A number of developments happened on Utah's environmental front in 2012, chief among them the state's progress to come up with an air pollution reduction plan that will pass federal muster.

Utah air quality regulators are not quite there for the Wasatch Front, but the implementation of a tailpipe inspections program in Cache County may get that area in compliance by 2014.

Environmental scientists will spend early 2013 crafting the hard limits on what industry can emit into Utah's skies, trying to shave levels of PM2.5 — tiny airborne particles — that clog lungs and impact public health.

While components of that plan are expected to be tough and even painfully expensive to adopt, the state risks invoking the ire of the Environmental Protection Agency if clean air standards are not met.

The good news on the pollution battle is that the Wasatch Front has prevailed in its efforts to zap ozone problems in the summer, with 14 air-monitoring stations registering no unacceptable limits over the past three years.

Some of these successes, detailed in the state Department of Environmental Quality's year-end report, include a multiyear, multiagency effort to dissect the cause of the ozone pollution that persists in the Uinta Basin.

A mild winter last year somewhat derailed data collection efforts by scientists to understand what kind of chemistry is at play, but preliminary information gathered will provide a roadmap for more analysis to continue in the coming months.

Air quality regulators, too, are taking part in a regional study that looks at air pollution that impacts the eastern section of Utah, national parks or monuments, and western Colorado.

Perhaps one of the most notable milestones of 2012 was the successful elimination at Deseret Chemical Depot of 45 percent of the nation's chemical weapons stockpile.

Destruction of the last nerve agent was completed well ahead of an international treaty deadline, and 95 percent of the secondary waste has been destroyed as well. The Tooele County facility will undergo an environmental makeover before it takes on a new purpose under the purview of the U.S. Army.

With an eye toward protecting water quality this year, the Utah Department of Environmental Quality directed improvements to the Weber River watershed area, including upper reaches of the Weber River, Chalk Creek and Summit County's East Canyon Creek.

The department also completed an intensive survey of the Jordan River in the central Salt Lake area in an attempt to better understand sources of pollution in the impaired waterway and what can be done to improve that river's health.

Joining forces with the federal government, counties, cities and advocacy groups, the state launched a cooperative monitoring agreement for the Great Salt Lake to enhance knowledge of its ecology and identify ways to best manage it for the multiple uses it supports, including waterfowl populations and industry.

To boost delivery of clean water to Utah homes, the department oversaw the allocation of nearly $26 million to 21 different water systems via system improvement projects.

Critics, however, blasted the state's issuance of a permit for the U.S Oil Sands PR Spring Project in eastern Utah, saying the oversight was not protective enough of potential groundwater in the area.

The state countered that an extensive network of wells revealed an absence of groundwater, and the tar sands operation had sufficient environmental controls in place.

In the remediation arena, the state and Salt Lake City are likely to see federal help to clean up a contaminated plume of groundwater on the east side near 700 South and 1600 East. The proposed Superfund designation that came in 2012 means an accelerated cleanup schedule to remove the contamination, which could grow larger over time if left alone.

Earlier this year, the department was called on to remove contaminated soil found when the city's Sugar House Streetcar Project was launched. More than 900 cubic yards of soil was cleared for the line, which is anticipated to be operational next year.

And in one of the department's most successful outreach efforts, this year saw nearly twice the number of radon tests it performed on potentially impacted homes — 8,467 to 2011's number at 4,236. Radon is an odorless gas and the second leading cause of lung cancer. The department said 30 percent of the homes it tested had levels higher than federal health standards.